I have a 96 PS190. We use it in saltwater quite frequently so of course it's time to replace the manifolds and risers. I have two questions. How can I determine the size of my riser? There are two options on the website, 3" or 3 1/2". Is a 3 1/2" riser a performance upgrade? Is one size standard? Also I'm going to order from ebasicpower.com and they have two different brands, Osco and GLM...what are your preferences on the two? The GLM is a little cheaper. Thanks for any help.

TMCNo1

03-22-2010, 03:57 PM

I have a 96 PS190. We use it in saltwater quite frequently so of course it's time to replace the manifolds and risers. I have two questions. How can I determine the size of my riser? There are two options on the website, 3" or 3 1/2". Is a 3 1/2" riser a performance upgrade? Is one size standard? Also I'm going to order from ebasicpower.com and they have two different brands, Osco and GLM...what are your preferences on the two? The GLM is a little cheaper. Thanks for any help.

Here is another option, http://www.skidim.com/products.asp?dept=1068, or any MasterCraft dealer can help.

deployedjosh

03-22-2010, 09:56 PM

Been there, done that. You're gonna want to stick with the stock size unless you're looking to reconfigure the muffler, etc. You can see the stock size by reading the exhaust hose ID or just measuring the flange after the hoses are off the riser. On my 1999 LTR, it was 3 1/2". I'm in the process of converting over to 3". I'm running it out to a FAE so it's not like there's any performance difference in dropping down to a smaller diameter. Either way, there's backpressure from the underwater exit. I am very happy with the GLM manifolds I got a few years back. At the time, the risers were still good, so I just replaced the manifolds. I recently developed an exhaust leak in the risers (pinholes in the recessed area for the allen bolts) hence the project.

I'll be posting up my final solution once I get it all done. Currently waiting on some 3" corrugated hose.

ebasicpower rocks! They're the cheapest by far of all the online retailers. I'd recommend getting some quality gaskets from Moore Performance. Dennis Moore is the author of one of the legendary tomes of marine engines, "Small Block Chevy Marine Performance."